Vacuum pump lubrication



March s, 1949. C. H. HAPGooD 2,463,871

VACUUM PUMP LUBRICATION 2 Sheets-Sheet l Filed June 1. 1945 March 8,1949. c. H. HAPGooD 2,463,871

VACUUM PUMP LUBRICATION Filed June 1, 1945 2 Sheets-Sheet 2 O lo N 0( miN Pennies Mier. s, 194e UNITED STATES PATENT; 2O F'FLIC VACUUM PUMPLUBRICATION cyrus Howard mpma, Nuaey, N. s.. signor to The De LavalSeparator Company, New York,

N. Y., a corporation of New Jersey Application June 1, 1945,1Serlal No.-597,024

-6Ciaims. 1

The type of vacuum. pump to which the present invention is particularlyapplicable comprises a housing', a hollow rotor within and eccentric tothe housing, an air inlet port to, and an air outlet port from, the airspace between rotor and housing, slidable vanes carried by the'rotor andarranged radially to the rotor shaft and which extend into said airspace and contact with the housing during the rotation of the rotor, adriving shaft to which the hollowrotor is secured, and a driving pulleyon the shaft. Vacuum pumps of this character are disclosed in the LeitchPatent No. 1,367,554, dated'February 8, 1921, the Hall Patent No.1,374,650, dated April 12, 1921, and patents issued tome No. 1,637,484,dated August 2, 1927, No. 1,684,395, dated September 18, 1928, and1,971,448 dated August 28, 1934.

The objects of'my invention are: to supply oil to the pump by the actionof the 'pump itself while in operation; to insure a continuouscirculation of oil through the pump, theV maintenance of a constant andpredetermined iilm 'of one 'end a cover plate i0 and, to the other orpulley end, a cover plate I2. These `three members enclose a pumpchamber i4.

A rotor il, having therein radial slots in which Ablades i8 slide andwhich open into holes 20 extending entirely through the rotor, isrotatably mounted inside the housing 8 with its bottom side in contactwith the bottom or" the housing 8 directly below the center of thehousing.

This rotor is mounted on a drive shaft 2i supl ported in bearings 22held in the end plates "i9 the rotor.

oil within the rotor chamber and the prevention of leakage vfrom 'theinterior to the exterior of the pump; to deliver the oil to such a pointin *he pump that it will seal the interior against n: leak of air fromthehigh to the low pressure points of the pump; to effect the return tothe oil reservoir of oil passing from the sealing zone into the workingspace of the pump; and' to insure that, after the operation of the pumphas stopped, the oil remaining in the pump will be returned to the oilreservoir or to the intake passages outside the pump, so -that'the pumpcan be easily started up even in the coldest weather.

A preferred embodiment of the invention is ldrown in the drawings, inwhich:

Figure ;1 is a sectional view through the base along the line i-l ofFigure 2, with the pump mounted on the base and from which one end platehas been removed.

Figure2 isa pian view of the base.

Figure 3 is an end View of a plate on the pulley side; and

Figure 4 is a sectional view through the pump housing along a line 4-4indicated on the end plate of Figure 3.

In the drawings the reference character 2 designates the base providedtherein with an oil reservoir 4 in which the oil is usually maintainedat the level i, and I is a. cover therefor, on which the motor 'la fordriving the pump may be mounted.

Mounted on and secured to one end of the base 2 is a pump housing Ihavingsecured to The housing is mounted on the base 2 as clearly shownin Figure ll with the packing member 29 between the base and thehousing.

39 designates the air inlet to the pump which extends into the baseproper and communicates by means of 'a vertical passage 32 with a crosspassage 34 in the housing. This cross passage extends laterally andcommunicates with air inlet ports 32 in the end plates which open intothe inlet'side of the rotor chamber clearly indicated in Figures 3 and4.

'3l `designates an outlet chamber in plate I2- which. like 'a similarchamber in plate I0, communicates with the discharge side of the rotorchamber and, through a cross passage 40, with a passage 42 extendingdownwardly to the oil reservoir l4.

Apipe 43 from the oil reservoir d, leads to a passage 44 in the pulleyend plate i2 and thence to a groove 4B which 'leads to the inside of therotor chamber l`4.

The operation of the device is as follows: In starting up any oil whichhas drained back into the inlet opening 30 will be sucked up into therotor chamber, vand the suction of the pump will draw cil through thepipe 43 and connections 44 and 46 into the near side of the rotorchamber and some of it will cross through passages 20 to the oppositeside of the rotor chamber. vSome of this oil will leak past the ends ofthe vrotor and -be carried with the air being pumped into the oilreservoir. Therein the oil will be separated from the air by gravity anda bame plate 48 and will collect in the reservoir, held by the wall 5l.An upwardly extending exhaust pipe (not shown) is connected to thethreaded opening 52 in the base 2.

A illler opening 54 for the oil reservoir is provided which may becovered with a cap having a bayonet type of oil gauge or other means ofmeasuring the amount of oil in the reservoir.

. The action of the pump will be such as to maintain a fllm-of oilbetween the end walls of the rotor chamber and the blades therein. Whenthe pump is stopped most of the oil therein will drain back from therotor chamber to the oil reservoir through the cross passage 40 andpassage 42 and through the portsy or openings 20 and passages 40 and 43.Any remaining oil will be-drained back into the inlet 30 and will besucked up when the pump is started in the next operation.

The above construction insures an adequate circulation of oil and themaintenance of a desired volume of oil within the rotor chamber. It isfound that if pipe 43 is closed off the vacuum at the bearings is aboutone half the vacuum at passage 34. The escape of oil from the pumpgthrough the exhaust is substantially entirely 'prevented After the pumpis stopped substan- \\tia1ly all of the oil will be drained from therotor chamber, so that, in restarting, the diiiiculty of hard startingwith congealed oil is avoided.

What I claim and desire to protect by Letters Patent is:

1. In a vacuum pump, a housing having a cylindrical rotor chamber, arotor mounted in the chamber with the rotor axis below the center of thechamber, the housing having a bottom surface and also separate air inletand air outlet passages opening through said bottom surface and leadingupwardly therefrom through the lower part of the housing to the bottomof the rotor chamber, said passages underlying'the rotor chamber andbeing located on opposite sides of a vertical plane along said axis, abase separable from the housing and having an upper surface supportingsaid bottom surface and opposed thereto, the base having air inlet andair outlet ports opening through said upper surface on opposite sides ofsaid vertical plane and registering, respectively, with the inlet andoutlet passages, the base also having on one side of said vertical planean air inlet leading to said inlet port and on the other side of saidplanean oil reservoir to which said outlet port leads, theoil reservoirextending laterally for a substantial distance beyond the rotor housingand below the level thereof, the base also having an air outlet from theoil reservoir, and a duct for delivering oil from the reservoir to therotor chamber.

2. A vacuum pump as defined in claim 1, in which said base includesl amovable cover offset laterally from the rotor housingiand overlying atleast part of the oil reservoir, the cover having a supporting surface,a motor for driving the pump and mounted on said cover surface, the partof the reservoir below the cover providing a large space for theoutgoing air to reduce the pressure thereof to permit the separation ofthe oil from ythe air.

3. In a vacuum pump, the combination of a housing having a cylindricalchamber, a plate at each end of the housing for closing the corre-Number Name Date y 1,051,360 Wisdom Jan. 21, 1913 1,056,859 Vernon Mar.25, 1913 1,142,544 Vernon et al June 8, 1915 1,776,921 Moessinger Sept.30, 1930 1,799,539 Smith Apr. 7, 1931 1,906,464 Hapgood May 2, 19331,923,600 Warner Aug. 22, 1933 1,973,063 Grier i Sept ll, 1934 FOREIGNPATENTS Number Country Date 259,367 Italy I 1928 sponding end of thechamber, each plate having an opening therethrough, a bearing mounted ineach end plate in said opening, a rotor in the chamber having a shaftsupported by said bearings, the axis of the rotor shaft being below thecenter of the rotor chamber, the housing having an air inlet passageextending downwardly from the bottom of the chamber on one side of thevertical center of the chamber and also having an air outlet passageextending downwardly from the bottom of the chamber of the opposite sideof the vertical center line of the chamber, a base on which said housingis supported, the base forming an oil reservoir and having an air outletport leading to the reservoir from said air outlet passage in thehousing, the base also having an air inlet port leading to said inletpassage in the housing, the wall of said opening in one of the endplates having an axial groove extending to the inner face of the plate,and an oil duct leading from the reservoir up to said groove fordelivering oil to the bearings. l

4. A vacuum pump as deiined in claim 3, in which said grooved plate hasan elongated port extending from the bottom of the chamber to above thehorizontal level of the rotor axis and forming part of said air inletpassage, the grooved plate also having a short port extending from thebottom of the chamber and terminating below said horizontal level andforming part of said outlet passage, the oil groove being located atapproximately said horizontal level and overlying said short port butseparated therefrom.

5. A vacuum pump as defined in claim 3, comprisingl also a cap securedto the outer face of each end plate over said opening in the plate.

6. A vacuum pump as dened in claim 3, comprising also a cap secured tothe outer face of each end plate, one of the caps covering one end ofthe shaft and the adjacent bearing to form an air-tight seal, the othercap covering the other bearing and having an opening for the shaft, anda seal within said last cap and engaging the shaft and the adjacent endplate to guard against leakage along'the shaft and said last bearing.

CYRUS HOWARD HAPGOOD.

REFERENCES CITED UNITED STATES` PATENTS

